Rotary gas burner assembly



Dec. 19, 1967 R REED ET AL ROTARY GAS BURNER ASSEMBLY 2 Sheets-Sheet 2' Filed July 16, 1965 //v VE/VTORS ROBE/P T 0. RE E D HERSHE L 'GOODN/G'H 7' United States Patent 3,358,736 ROTARY GAS BURNER ASSEMBLY Robert D. Reed and Hershe] Goodnight, Tulsa, Okla., assignors to John Zink Company, Tulsa, Okla., a corporation of Delaware Filed July 16, 1965, Ser. No. 472,416 2 Claims. (Cl. 158-99) ABSTRACT OF THE DISCLOSURE The invention comprises a rotary burner head having discharge ports therein so that fuel issuing therefrom rotates the burner head. The burner housing is formed to present an annular ledge adjacent the arcuate path of movement of the burner head. Means are provided to deliver a small amount of fuel to the ledge where it burns stably to maintain ignition of the main portion of fuel.

The present invention relates to apparatus for the combustion of fuel and more particularly pertains to a rotary burner wherein the fuel issuing from discharge ports develops reaction which drives the burner head and fan blades to promote mixing of air with the fuel and the invention includes means promoting stable commustion of the fuel.

It is known in the art to which the invention pertains to release gaseous fuel through discharge ports carried by hollow arms which radiate from the hub of a burner head which is mounted for rotation whereby the reactive energy produced by the jets of fuel serves to rotate the burner head in a direction opposite to the direction at which the fuel is discharged. Such an assembly is disclosed in the Dennis Patent 2,177,245 and the fan blades carried by the rotating burner head function to deliver air into the presence of the fuel discharged from the hollow arms of the burner head. Such a rotary burner functions satisfactorily when the speed of rotation is substantially constant but when the rate of rotation changes in response to larger or smaller quantities of fuel released the prior devices exhibit undesired and even dangerous characteristics. An abrupt change in the pressure at which the gaseous fuel is supplied to the burner head develops unstable combustion to such an extent that prior rotary burners lose ignition and there have been explosions in furnaces and fire boxes as a consequence of such unstable characteristics.

It is an object of the present invention to provide a rotary burner assembly comprising a burner head carrying propeller means in combination with an annular ledge adjacent the arcuate path of movement of the free ends of the hollow arms onto which a minor portion of the fuel is delivered where it burns stably to maintain ignition of the major portion of the fuel discharged from the hollow arms to thereby provide stable operation of the burner even though there may be abrupt changes in the rate at which the fuel is discharged from the burner head.

Another object of the invention is to provide an annular ledge adjacent the path of movement of the free ends of the arms of the rotary burner head and to provide structure for delivering a small portion of the gaseous fuel onto the ledge where it is shielded from the secondary air to develop eddies at the downstream face of the ledge wherein the minor portion of the fuel burns stably and serves to maintain kindling of the remainder of the fuel discharged by the burner head.

Other objects and features of the invention will be appreciated and become apparent to those skilled in the art to which the invention pertains as the present disclosure 'ice proceeds and upon consideration of the following detailed description taken in conjunction with the accompanying drawings wherein an embodiment of the invention and a modification are disclosed.

In the drawings:

FIG. 1 is an axial sectional view of a burner assembly embodying the invention.

FIG. 2 is an end elevational view taken generally on the line 22 of FIG. 1.

FIG. 3 is a sectional view taken on the line 33 of FIG. 2 and on a larger scale.

FIG. 4 is an enlarged fragmentary sectional View taken on the line 4-4 of FIG. 2.

FIG. 5 is a sectional view of a modified burner and ceramic assembly.

FIG. 6 is a fragmentary sectional view on a larger scale taken on the line 66 of FIG. 5.

The invention is directed to a rotary burner in combination with a ceramic member which surrounds the downstream end portion of the burner head to provide an assembly which is stable in operation and provides continuous rekindling of the fuel discharged by the hollow arms of the rotating burner head even when there is an abrupt change in the volume of fuel discharged by the burner head in response to alteration of the pressure at which the fuel is supplied to the burner assembly. The ceramic member is shown at 10 and it may have any desired exterior shape for mounting in an opening in a furnace wall. The ceramic member is provided with an opening 11 into which an annular housing 12 is fitted and which forms a stationary or fixed part of the assembly. The downstream end portion of the housing 12 is accommodated in the opening 11 and may be secured to the ceramic member 10 in any suitable manner. The upstream end of the housing 12 is provided with circumferentially spaced lugs one of which is shown at 14 in FIG. 1. The lugs 14 provide means for mounting a stationary air door 16 adjacent the free end of the housing 12. An adjustable air door 17 cooperates with the stationary air door 16 to admit controlled quantities of air into the interior of the housing 12 for movement into the space to be fired and over the burner head as hereinafter described.

The assembly includes a sleeve 18 supported on the stationary air door 16 by circumferentially spaced lugs and cap screws one of which is shown at 19. The sleeve 18 is thus supported in fixed relationship with respect to the housing 12. A tubular shaft 22 extends through the sleeve 18 and supports a burner head unit 21 for rotation. Free rotation of the hollow shaft 22 and the burner head 21 is faciliated by ball bearing assemblies 23 arranged between the sleeve 18 and the shaft 22. The downstream end of the sleeve 18 is closed with respect to the periphery of the tubular shaft 22 by an annular disc shaped member 24 attached to the downstream end of the sleeve 18. The upstream end of the shaft 22 rotates in sealed relationship with respect to a boss 26 formed on the stationary air door 16. A suitable supply pipe (not shown) may be connected to the interiorly threaded boss 26 so that gaseous fuel under pressure is delivered into the tubular shaft 22.

The burner head unit 21 may be formed in any suitable manner and has a hollow hub forming a reservoir for fuel .as shown in FIG. 1. The burner head unit includes a plurality of radially disposed hollow arms 31 which may be of any desired number. In the embodiment shown in the drawings four such arms are provided and they may be threaded into the hub portion 32 of the burner head. The downstream end of the hub is closed by means of a disc 33 havin a conical surface 34 for diverting the fuel into the hollow arms 31.

The burner head unit 21 includes a plurality of impeller blades 36 which are shaped to move air furnaceward when the burner head unit 21 rotates in a clockwise direction as indicated by the arrow in FIG. 2. The impeller or fan blades 36 are circumferentially spaced from each other and are desirably disposed with one located upstream of each hollow arm 31 whereby each propeller blade shields an arm 31 as the air moves through the opening 37 (FIG. 2). The burner head unit 21 may be formed of several component parts which are maintained in assembled relationship and secured to the tubular shaft 22 by cap screws 38. These cap screws also maintain the disc member 33 in a position closing the downstream end of the hub of the burner head.

A feature of the present invention pertains to an annular ledge on the ceramic member adjacent the path of movement of the free ends of the hollow arms 31. This ledge has a surface 41 which faces downstream of the assembly and is disposed substantially at right angles to the axis about which the burner head unit rotates. The plane of the downstream face 41 is substantially flush with the downstream edge portion of the free ends of the hollow arms 31 as shown in FIGS. 1 and 4.

Each hollow arm 31 is provided with a plurality of discharge ports 46. The discharge ports 46 are of such number and size as to provide for the discharge of from eighty-five to ninety-eight percent of the fuel delivered into the hollow hub of the burner head unit 21. A plane 47 defined by the center line of all of the hollow arms 31 and at right angles of the axis of the burner assembly is indicated in FIGS. 1 and 4. The axis of each discharge port 46 is disposed at an angle A of from twenty to thirty degrees with respect to the plane 47 as shown in FIG. 3. The discharge ports 46 when disposed at such angles provide reaction energy for driving the burner head unit 21 and the angular disposition of the ports 46 also serve to impart shape to the flame. When the discharge ports are provided at an angle of about twenty degrees with respect to the plane 47 maximum reactive energy is developed and such a disposition of the ports creates a wide spreading flame of the fuel. The reactive energy developed when the axis of the discharge ports 46 are disposed at an angle of about thirty degrees with respect to the plane 47 is less and close to the minimum value tolerable for driving the burner head unit 21 but the flame is then of less width.

In the embodiment shown in FIGS. 1 through 4 at least one kindling orifice 51 is provided adjacent the free end of each hollow arm 31 as best shown in FIG. 4. The axis of each discharge orifice 51 is disposed at an angle B from about thirty to forty-five degrees with respect to the center line of the associated hollow arm 31 as shown in FIG. 4. A projection of the axis of each orifice 51 is also at right angles to the plane 47. The discharge orifices 51 are of such size that a minor portion of the gaseous fuel escapes therethrough and in a quantity that may vary from two to fifteen percent of the gaseous fuel delivered to the burner head unit. The fuel escaping through the orifices 51 does not impart any reactive energy to drive the burner head unit but this minor portion of the fuel is discharged over the ledge on the ceramic member 10 and along the surface 41. Eddy currents of the fuel and air are developed along the sur face 41 which are shielded from the air moving furnaceward through the opening 37. The gaseous fuel upon ignition burns constantly along the annular ledge or surface 41 to kindle and rekindle the remainder or major portion of the fuel which escapes through the discharge ports 46 even when there is an abrupt change in the pressure at which the fuel is supplied to the burner head.

A modification is shown in FIGS. 5 and 6 wherein the hollow arms 31a are devoid of orifices 51. In this embodiment gaseous fuel is supplied to the surface 41 of the ledge by a plurality of pipes 61 one of which is shown in FIG. 5. The pipes 61 extend through suitable openings in the body of the ceramic member 100. A discharge port 62 is provided in each gaseous fuel supply pipe 61. The axis of each port 62 is disposed to discharge a small quantity of gaseous fuel generally tangentially along the downstream facing surface 41. This minor quantity of fuel upon ignition burns stably and provides ignition of the major portion of the fuel which escapes from the discharge ports in the hollow arms 310.

While the invention has been described with reference to particular structural features in a general overall assembly it will be appreciated that changes may be made in the elements and in the combination. Such modifications and others may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

What We claim and desire to secure by Letters Patent is:

1. In a rotary gas burner assembly, a ceramic member having an annular interior surface, a hub structure supported for rotation within said ceramic member, a plurality of hollow arms radiating from said hub structure, means for supplying gaseous fuel into said hub structure for movement into said arms, each arm having a plurality of discharge ports disposed in one general direction with respect to the rotation of the hub structure for escape of a major portion of said gaseous fuel whereby the reactive energy of the escaping fuel develops rotation of the hub structure and the hollow arms, impeller blades carried by said hub structure for moving air through said annular interior surface, a ledge carried by the ceramic member having a downstream facing surface substantially flush with the path of movement of the free ends of said hollow arms, each hollow arm having an orifice therein adjacent the free end thereof for discharging a minor portion of gaseous fuel along said downstream facing surface, and the axis of each of said orifices being disposed at an angle from about thirty to forty-five degrees with respect to the center line of the hollow arm.

2. In a rotary gas burner assembly according to claim 1 wherein the axis of each orifice is disposed substantially at right angles to the plane of rotation of said arms.

References Cited UNITED STATES PATENTS 1,903,317 4/ 1933 Tibbot. 2,327,512 8/1943 Dennis l5899 X 2,260,166 10/1941 Cope l581l5 X 2,267,709 12/ 1941 Graham 158-1l8 3,033,273 5/1962 Zink et a] 1587 FREDERICK L. MATTESON, JR., Primary Examiner.

H. B. RAMEY, Assistant Examiner. 

1. IN A ROTARY GAS BURNER ASSEMBLY, A CERAMIC MEMBER HAVING AN ANNULAR INTERIOR SURFACE, A HUB STRUCTURE SUPPORTED FOR ROTATION WITHIN SAID CERAMIC MEMBER, A PLURALITY OF HOLLOW ARMS RADIATING FROM SAID HUB STRUCTURE, MEANS FOR SUPPLYING GASEOUS FUEL INTO SAID HUB STRUCTURE FOR MOVEMENT INTO SAID ARMS, EACH ARM HAVING A PLURALITY OF DISCHARGE PORTS DISPOSED IN ONE GENERAL DIRECTION WITH RESPECT TO THE ROTATION OF THE HUB STRUCTURE FOR ESCAPE OF A MAJOR PORTION OF SAID GASEOUS FUEL WHEREBY THE REACTIVE ENERGY OF THE ESCAPING FUEL DEVELOPS ROTATION OF THE HUB STRUCTURE AND THE HOLLOW ARMS, IMPELLER BLADES CARRIED BY SAID HUB STRUCTURE FOR MOVING AIR THROUGH SAID ANNULAR INTERIOR SURFACE, A LEDGE 